non-group-messages from non-Delta-Client to multiple recipients do not create ad-hoc group

[r10s]

i received a mail form a non-Delta-Client today, sent to three recipients - afaik, these kind or mails should create an ad-hoc group with the recipients (or maybe resue an existing group), however, the mail show up in the normal one-to-one-chat.

this is bad, as replies are not sent to all reicpient, also, it is invisible to the Delta user who are the recipients.

similar forum entry: https://support.delta.chat/t/deltachat-doesnt-group-messages-as-before-regression/829

[r10s]

tested this with a fresh delta-account, show-classic-mails=all - everything works as expected, so, not sure if my description above is really correct, i am failing to to reproduce it.

[r10s]

k, i found an issue:

• setup new delta chat for Alice-Delta, show-classic-mail=accepted
• send message from Alice to Bob-NonDelta (this creates Bob as a contact)
• send a ad-hoc-group-messages from Bob-NonDelta to Alice-Delta and Claire

=> the ad-hoc-group-message will not create an ad-hoc-group for Alice